Sesamin is one of the principal lignan compounds in sesame and is contained in sesame seeds in amounts of 0.1-0.5%. In contrast, episesamin which is an isomer of sesamin does not naturally occur in sesame seeds, but when sesame oil is passed through refining steps (decolorizing and deodorization) to obtain salad oil, sesamin undergoes epimerization to give episesamin as a by-product (Non-Patent Document 1), and sesamin-class compounds refined from the sesame oil are known to contain sesamin and episesamin in proportions of nearly 1:1 by weight ratio (Non-Patent Document 2).
As regards the sesamin-class compounds (hereinafter used as the collective term for sesamin and its analogs; sesamin analogs may be exemplified by episesamin, as well as sesamin, sesaminol, episesaminol, sesamolin, and the like), documents and the like have shown that they have the following physiological activities: the action of inhibiting the metabolism of cholesterol or bile acid in the intestines; the action of alleviating the symptoms of withdrawal from alcohol intoxication; the action of improving hepatic functions; the action of in vivo stabilization of highly unsaturated fatty acids (Patent Document 1); the action of inhibiting Δ5-desaturase; the action of suppressing migraine; the action of inducing apoptosis in human leukemic cells; the action of suppressing the oxidative decomposition of melatonin; the action of ameliorating inflammatory disease (amyotrophic lateral sclerosis); the actions of combating inflammation and protecting against infection; an allergy preventing or ameliorating action by use in combination with oils or fats containing at least one of α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid (Patent Document 2); the action of scavenging active oxygen; the action of preventing sickness from drinking; the action of adjusting the balance between omega-6 and omega-3 unsaturated fatty acids (Patent Document 3); the action of suppressing the generation of lipid peroxides; the breast cancer suppressing action; the anti-hypertensive action; the body fat reducing action; and the action of suppressing prostatomegaly by use in combination with saw palmetto.
Patent Document 1: Official Gazette of JP 11-269456 A
Patent Document 2: Official Gazette of JP 5-58902 A
Patent Document 3: Japanese Patent No. 3512196
Non-Patent Document 1: Namiki et al., “Goma-Sono Kagaku to Kinousei (Sesame-Its Science and Functions)”, Maruzen Planet Co., Ltd. (1998)
Non-Patent Document 2: Fukuda, Y. et al., J. Am. Oil Chem. Soc., 63, 1027-1031 (1986)